The article presents a numerical examination of the influence of selected design parameters of a CFR2 composite-foam cover rail of a roadside barrier (described in previous publications by the same author) on the course of the TB11 virtual crash test. The crash tests were carried out on a modified SP-05/2 barrier of the N2-W4-A class, forming a horizontal concave arc with a radius of 150 m. During the tests, a passenger car with a mass of 900 kg hit the barrier with a velocity of 100 km/h at an angle of 20 °. The CFR2 cover rail consists of polyester-glass composite segments partly filled with polyurethane foam. The cover rail cross-section fits the B-type guiderail profile of the barrier. The numerical computations were carried out in the LS-Dyna environment, with using the Geo Metro vehicle model taken from the NCAC website and subjected to necessary modifications. The results of the virtual crash tests were analysed in respect of all the qualitative and quantitative parameters required by standards PN-EN 1317-1:2010 and PN-EN 1317-2:2010. The analyses carried out showed the design of the CFR2 cover rail to be correct and sufficient for the TB11 crash test results to be accepted.